Control for flexible parawing



March 21, 1967 F. M. ROGALLO ET AL 3,310,261

CONTROL FOR FLEXIBLE PARAWING Original Filed Jan. 17, 1964 2Sheets-Sheet 1 FIG. 2

INVENTORS FRANCIS M. ROGALLO WILLIAM C. SLEEMAN, JR.

ffl) 0% W/WM ATTORNEY 5' March 21, 1967 F. M. ROGALLO ET L 3,310,261

CONTROL FOR FLEXIBLE PARAWING Original Filed Jan. 17, 1964 2Sheets-Sheet 2 FIG. 4

FIG. 5

INVENTORS' FRANCIS M. ROGALLO WILLIAM C. SLEEMAN, JR

BY Jim.

ATTORNEY S United States Patent CONTROL FOR FLEXIBLE PARAWING Francis M.Rogallo and William C. Sleeman, Jrz, both of Newport News, Va.,assignors to the United States of America as represented by theAdministrator of the National Aeronautics and Space AdministrationContinuation of application Ser. No. 338,535, Jan. 17,

1964. This application Feb. 9, 1966, Ser. No. 551,815 Claims. (Cl.244-44) The invention described herein may be manufactured and used byor for the Government of the United States of'America for governmentalpurposes without the payment of any royalties thereon or therefor.

This application is a continuation of patent application Ser. No.338,535, filed Jan. 17, 1964, entitled, Control for Flexible Parawing,now abandoned.

This invention relates to a control for a flexible wing vehicle, andmore particularly to a boltrope control for a flexible wing aircraft.

Due to the increased use of the flexible wing as an aerodynamic liftsurface for various types of air vehicles, such as gliders, powereddrones, aircraft, and wings for the recovery of rocket boosters andspace capsules, it has become necessary to provide an effective meansfor controlling the flexible wing. To date, the principle technique ofcontrol for a vehicle having a flexible wing lift surface is to shiftthe center of gravity of the payload with respect to the flexible wingsurface. Although this type of control is satisfactory to a degree, ithas been found to have many disadvantages. With this type of control theforces required to shift the payload with respect to the wing for trimover an appreciable speed range may be large and not have a stablevariation with speed. Also, response of the vehicle may be slow due tothe shifting of the large load. Furthermore, with the increasing size ofvehicles utilizing the flexible wing, it has become impractical to shiftthe relative position of the wing of the vehicle center of gravity dueto the weight and complexity of the mechanism necessary to accomplishthe shift.

The use of the boltrope control, on the other hand, overcomes many ofthe above difliculties. It greatly reduces the control forces required.Control is accomplished by merely shortening and lengthening theboltrope in the trailing edge of the flexible wing membrane. Thus, asthe boltrope is shorteded and lengthened the wing membrane is shortenedand lengthened the same amount to provide control of the vehicle. Bychanging the wing configuration symmetrically pitch control is providedfor whereas asymmetrical variation of the wing planform will provideroll control. Response of the vehicle is dependent only upon the rate atwhich the boltrope is shortened and lengthened, this speed being readilydeterminable by conventional servo mechanism.

It is, therefore, an object of the present invention to provide acontrol for a flexible wing vehicle by use of a boltrope.

Still another object of thisinvention is to provide a control for aflexible wing vehicle which will give rapid vehicle response.

Yet another object of this invention is to provide a control for aflexible wing vehicle which requires minimum control forces.

Another object of this invention is to provide a control for a flexiblewing vehicle which is of a simple engineering design, economical tomanufacture and maintain and is highly reliable.

Yet another object of this invention is to provide a flexible wingcontrol system for utilizing a boltrope with a simple servo system.

A further object of the invention is to provide a control of theboltrope type for a flexible wing vehicle where- 3,31%,261 Patented Mar.21, 1957 in the length of the boltrope may be varied by changing theposition of a portion of the wing superstructure.

Yet another object of the invention is to provide a control of theboltrope type for a flexible wing vehicle wherein symmetrical variationof the boltropes provide pitch control and asymmetrical variation of theboltropes provide roll control.

These and other objects and advantages of the invention will become moreapparent upon reading the specification in conjunction with theaccompanying drawings.

In the drawings:

FIG. 1 is a perspective view of a vehicle wherein the payload is slungbelow the flexible wing structure having a boltrope control;

FIG. 2 is a plan view showing the flexible wing of the vehicle partiallycut away to reveal the position of the boltrope relative to the flexiblewing membrane;

FIG. 3 is a side elevational view showing diagrammatically the mechanismutilized to vary the length of the boltrope;

FIG. 4 is a side elevational view of a section of the flexible wingstructure showing a section of the keel of the flexible wing universallyconnected to the remainder of the keel, and servo means for displacingthe hinged section to vary the length of the boltropes and FIG. 5 is anend view of the vehicle utilizing the control mechanism of FIG. 4,showing the various con figurations the wing membrane assumes to providecontrol of the vehicle.

Basically, this invention relates to a control of the boltrope type asapplied to the flexible wing of a flexible wing vehicle. Generallyspeaking, the flexible wing would include a superstructure of a keel andleading edge members connected to an extremity thereof and projecting atan angle therefrom so as to generally form an overall triangularconfiguration. A flexible membrane is connected to the leading edgemembers and keel, and boltropes passed through enclosures formed in thetrailing edge of the flexible membrane and fixed to mechanism forvarying the length of the boltropes. Pitch control of the vehicle isaccomplished by shortening and lengthening the boltropes symmetricallyand by varying the length of the boltropes asymmetrically the roll ofthe vehicle can be controlled.

Referring now more specifically to the details of the invention, theflexible wing vehicle is designated generally by the reference numberal10.

In the vehicle shown in FIG. 1 the wing 18 is connected to a payload 12by shrould lines 13. The payload 12 is thus suspended below the wing;however, it should be understood that it is within the broadest aspectof the invention to construct the flexible wing vehicle such that thepayload is an integral part of the wing superstructure. The payload 12may be most any item which is capable of being airlifted, for example, abooster, a space capsule, a cargo carrier and many other items.

The wing 18 of the flexible wing vehicle has superstructure whichincludes a keel 19 and leading edge members 20 and 21. The leading edgemembers 20 and 21 are connected to the forward extremity of the keel 19in a conventional manner and disposed at an angle thereto as clearlyshown in FIG. 1. The keel and leading edge members may be constructedfrom various materials such as metal, plastic, and/ or cloth. Themembers may also take various configurations such as a one-piece solidconstruction, a tubular member, a truss arrangement with a suitablecovering or may be inflatable.

The flexible wing membrane 241 is fixed to the leading edge members 20and 21 and to a common line along the keel 19. The membrane may beconstructed from various materials, may of the tough, lightweight,commercially available plastics being particularly suited for er thispurpose, as well as some of the high strength cloths now available. Asviewed in FIG. 1, it is readily apparent that the wing is divided intopanels or sections, the membrane connected between the keel 19 and theleading edge member 20 forming one panel and the membrane connectedbetween the keel 19 and leading edge member 21 another panel. The leftpanel, as viewed in FIG. 1, or the lower panel as viewed in PEG. 2, isprovided with a boltrope enclosure or channel 25. This channel is formedin the trailing edge of the wing membrane and may be constructed bymerely turning over the edge of the material and fixing it upon itselfin a well known manner. The enclosure may also be superimposed on themembrane and secured thereto by known techniques. The other panel has asimilar enclosure 26. A left boltrope 27 is threaded through theenclosure 25 and housed therein. A right boltrope 28 is located withinthe enclosure 26. The boltrope may be constructed from materials such asnylon cord or wire. One end of the boltrope 27 is fixed to the leadingedge member 2d and the one end of the boltrope 28 is fixed to theleading edge member 21. The other end of the boltropes are secured tothe control mechanism now to be described.

One form of control mechanism is illustrated in FIG. 3 and designatedgenerally by the reference numeral 39. The control mechanism 39 is shownhoused within the keel 19; however, it is to be understood that theboltrope: might be controlled from the leading edge members or thepayload. The control mechanism 30 includes a left boltrope control motor32 which has a shaft 33 and a winding drum 34 fixed to the shaft 33. Theboltrope 26 is fixed to the drum 34 and wound thereabout. A rightboltrope control motor 36 having a drive shaft 37 and a winding drum 38are concentrically disposed about the shaft 33. The boltrope 28 issecured to and wound about the drum 38. The concentric arrangement ofthe right boltrope control motor 36 and its components is necessary onlywhen the keel 19 is of very limited diameter, otherwise, it may beplaced adjacent the left boltrope control motor and be of similardesign. The motors 32 and 36 are reversible to provide for lengtheningor shortening the boltropes. The motors may be controlled from thepayload, from a cockpit if the vehicle is manned, or remotely byconventional electronic equipment (not shown). Obviously, drum windingscould be done manually.

FIG. 4 shows a modified flexible wing control designated generally bythe reference numeral 45. In this arrangement the keel 47 is jointedhaving a trailing edge section or keel control arm 49 connected togetherby a universal hinge or joint 48 (shown diagrammatically). The portion49 of the keel is designed to have freedom of movement in at least thevertical direction as well as in the horizontal direction.

Horns 50 are fixed to the keel control arm at 90 degree intervalsthereabout. Two of the horns are in a vertical plane passing through thekeel and the other two in a horizontal plane passing through the keel.Actuator cables 52 are connected to the horns and to winding drums 54located forward on the keel or in the payload. Manual control could bereadily accomplished by fixing the cables to conventional linkage (notshown).

Operation From the above description the operation of the control is nowbelieved to be readily apparent. Considering first the control mechanism30, wherein the boltrope control motors are actuated such that theboltropes 27 and 28 are simultaneously shortened to the same degree, itis clear that the configuration of both panels of the flexible wingwould be changed to the same degree. This would cause the wing to pitchdownward. Conversely, simultaneously lengthening the boltrope wouldcause the wing to pitch upward from a trimmed condition. Inasmuch as theboltrope is in tension until the boltrope length exceeds the length ofthe fabric at the trailing edge, the boltrope has to be driven in onlyone direction, that is, to pull it in. The leading edge members 20 and21 are angularly rigid with respect to the keel 19; thus, the flexiblemembrane is drawn in the nature of a draw string on a sack. By operatingthe control motors 32 and 36 asymmetrically the boltrope 27 is shortenedand the boltrope 28 lengthened or vise versa and the wing is caused toroll,

Control is accomplished in much. the same manner by the controlmechanism 45 wherein a payload 56 is suspended from a flexible winghaving a wing membrane 46. In this arrangement the actuator cables 52,in the vertical plane, are taken in and played out to move control arm4-9 up and down. With this movement, the boltropes are simultaneouslyshortened, relative to the distance between the leading edge member andkeel proper, thereby providing for pitch control. When the keel controlarm 49 is displaced sideways by taking in and playing out, the actuatorcables in the horizontal plane one of the boltropes is shortened and theother lengthened relatively providing for roll control. This is believedclearly illustrated in FIG. 5 wherein four possible positions of thekeel control arm 49 are shown together with the corresponding positionof the wing shown in dotted lines.

From the above description, it is believed clear that the inventionherein disclosed provides an improvement in the control of flexible wingvehicles. The control is entirely independent of the position of thepayload. Use of the boltrope to change the wing planform is an extremelysimple device to provide control of the vehicle. Obviously, the forcesnecessary to shorten the boltrope are insignificant compared to theforces necessary to shift the payload with respect to the wing as isdone in prior art arrangements. The control mechanism used forshortening the boltrope is also of simple design and a fraction of theweight of previously utilized equipment. Since the boltropes aredirectly connected to the control mechanisms, the control is rapid andresponse immediate. The boltrope control is adaptable to the flexiblewing configuration regardless of the size or configuration of the wing.

While a preferred embodiment of this invention and a modificationthereof has been described, it will be understood that othermodifications and improvements may be made thereto. Such of thesemodifications and improvements as incorporate the principles of thisinvention are to be considered as included in the hereinafter appendedclaims unless these claims by their language expressly state otherwise.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:

We claim:

1. A control for an aerodynamic vehicle or the like comprising: a wingedvehicle having structural members; flexible wing membrane being securedto said structural members; a tensionable member guided by andconforming substantially to the shape of said flexible membrane andbeing movable with respect thereto; and means for varying the tension onsaid tensionable member to alter the shape of said wing membrane andthereby provide a flight control for the vehicle.

2. A control for an aerodynamic vehicle or the like as in claim 1wherein the tensionable member is a boltrope carried by said flexiblemembrane; and said means for varying the tension is means for changingthe length of said boltrope.

3. A control for aerodynamic vehicle or the like as in claim 2 whereinsaid boltrope is carried by the trailing edge of said flexible membrane.

4. A control for an aerodynamic vehicle or the like as in claim 2wherein the'means for changing the length of the boltrope is a motorizeddrum.

5. A control for an aerodynamic vehicle or the like as in claim 2wherein said means for changing the length of the boltrope is a movableportion of at least one of said winged vehicle structural members; andmeans for actuating the movable part of said winged vehicle structuralmember.

6. A control for a vehicle capable of flight comprising: a wingedvehicle; said vehicle wing having a wing superstructure comprised of akeel and leading edge members; wing structure of said vehicle being aflexible membrane connected to said leading edge members and to saidkeel forming wing panels; a boltrope carried within each of said panels;and means for changing the length of said boltrope to alter the shape ofsaid wing and thereby control the flight of said vehicle.

7. A control for a vehicle capable of flight as in claim 6 wherein saidmeans for altering the length of said boltropes includes mechanism forsymmertical and asymmetrical length variation of said boltropes.

8. A control for a vehicle capable of flight as in claim 6 wherein saidmeans for changing the length of said boltropes includes winding drums,and power means connected to said drums for simultaneously shorteningsaid boltropes or shortening one of said boltropes and lengthening theother boltrope.

9. A control for a vehicle capable of flight as in claim 6 wherein aportion of said keel is hinged; said boltropes being fixed to the hingedportion of said keel; and power means connected to the hinged portion ofsaid keel to displace said hinged portion to shorten said boltropes orshorten one of said boltropes and lengthen the other.

10. A control for a vehicle capable of flight as in claim 6 wherein saidboltropes are carried in enclosures formed in the trailing edge of saidpanels and being slidable therein.

References Cited by the Examiner UNITED STATES PATENTS 3/1957Fitzpatrick. 6/1964 Girard.

1. A CONTROL FOR AN AERODYNAMIC VEHICLE OR THE LIKE COMPRISING: A WINGEDVEHICLE HAVING STRUCTURAL MEMBERS; FLEXIBLE WING MEMBRANE BEING SECUREDTO SAID STRUCTURAL MEMBERS; A TENSIONABLE MEMBER GUIDED BY ANDCONFORMING SUBSTANTIALLY TO THE SHAPE OF SAID FLEXIBLE MEMBRANE ANDBEING MOVABLE WITH RESPECT THERETO; AND MEANS FOR VARYING THE TENSION ONSAID TENSIONABLE MEMBER TO ALTER THE SHAPE OF SAID WING MEMBRANE ANDTHEREBY PROVIDE A FLIGHT CONTROL FOR THE VEHICLE.